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110 lines
4.2 KiB
110 lines
4.2 KiB
/*
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* Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef MEDIA_BASE_H264_PROFILE_LEVEL_ID_H_
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#define MEDIA_BASE_H264_PROFILE_LEVEL_ID_H_
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#include <map>
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#include <string>
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#include "absl/types/optional.h"
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#include "common_types.h" // NOLINT(build/include)
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#include "rtc_base/system/rtc_export.h"
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namespace webrtc {
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namespace H264 {
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// Map containting SDP codec parameters.
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typedef std::map<std::string, std::string> CodecParameterMap;
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// All values are equal to ten times the level number, except level 1b which is
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// special.
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enum Level {
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kLevel1_b = 0,
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kLevel1 = 10,
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kLevel1_1 = 11,
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kLevel1_2 = 12,
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kLevel1_3 = 13,
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kLevel2 = 20,
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kLevel2_1 = 21,
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kLevel2_2 = 22,
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kLevel3 = 30,
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kLevel3_1 = 31,
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kLevel3_2 = 32,
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kLevel4 = 40,
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kLevel4_1 = 41,
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kLevel4_2 = 42,
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kLevel5 = 50,
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kLevel5_1 = 51,
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kLevel5_2 = 52
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};
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struct ProfileLevelId {
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constexpr ProfileLevelId(Profile profile, Level level)
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: profile(profile), level(level) {}
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Profile profile;
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Level level;
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};
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// Parse profile level id that is represented as a string of 3 hex bytes.
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// Nothing will be returned if the string is not a recognized H264
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// profile level id.
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absl::optional<ProfileLevelId> ParseProfileLevelId(const char* str);
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// Parse profile level id that is represented as a string of 3 hex bytes
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// contained in an SDP key-value map. A default profile level id will be
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// returned if the profile-level-id key is missing. Nothing will be returned if
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// the key is present but the string is invalid.
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RTC_EXPORT absl::optional<ProfileLevelId> ParseSdpProfileLevelId(
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const CodecParameterMap& params);
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// Given that a decoder supports up to a given frame size (in pixels) at up to a
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// given number of frames per second, return the highest H.264 level where it
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// can guarantee that it will be able to support all valid encoded streams that
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// are within that level.
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RTC_EXPORT absl::optional<Level> SupportedLevel(int max_frame_pixel_count,
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float max_fps);
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// Returns canonical string representation as three hex bytes of the profile
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// level id, or returns nothing for invalid profile level ids.
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RTC_EXPORT absl::optional<std::string> ProfileLevelIdToString(
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const ProfileLevelId& profile_level_id);
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// Generate codec parameters that will be used as answer in an SDP negotiation
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// based on local supported parameters and remote offered parameters. Both
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// |local_supported_params|, |remote_offered_params|, and |answer_params|
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// represent sendrecv media descriptions, i.e they are a mix of both encode and
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// decode capabilities. In theory, when the profile in |local_supported_params|
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// represent a strict superset of the profile in |remote_offered_params|, we
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// could limit the profile in |answer_params| to the profile in
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// |remote_offered_params|. However, to simplify the code, each supported H264
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// profile should be listed explicitly in the list of local supported codecs,
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// even if they are redundant. Then each local codec in the list should be
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// tested one at a time against the remote codec, and only when the profiles are
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// equal should this function be called. Therefore, this function does not need
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// to handle profile intersection, and the profile of |local_supported_params|
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// and |remote_offered_params| must be equal before calling this function. The
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// parameters that are used when negotiating are the level part of
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// profile-level-id and level-asymmetry-allowed.
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void GenerateProfileLevelIdForAnswer(
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const CodecParameterMap& local_supported_params,
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const CodecParameterMap& remote_offered_params,
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CodecParameterMap* answer_params);
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// Returns true if the parameters have the same H264 profile, i.e. the same
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// H264::Profile (Baseline, High, etc).
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bool IsSameH264Profile(const CodecParameterMap& params1,
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const CodecParameterMap& params2);
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} // namespace H264
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} // namespace webrtc
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#endif // MEDIA_BASE_H264_PROFILE_LEVEL_ID_H_
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